Girl on the Train author on her novel's runaway success

After ten years as a successful financial journalist and with four romantic novels under her belt, what led Paula Hawkins to write a gripping psychological thriller?

"I was in quite a dark and desperate place, and that's actually not a bad place to be as a thriller writer," she tells Shad with a laugh.

The months she spent in that place certainly paid off — the end result, The Girl on the Train, has quickly become the fastest-selling adult novel of all time. It's been billed as the next Gone Girl and a Hollywood adaptation is already underway.

Hawkins joins Shad to talk about the book's runaway literary success, why she's fascinated by ordinary people doing terrible things, and what all of this says about psychological thrillers set in the domestic sphere.